1. Field of the Invention
The present invention relates to a technique of defect repair that is performed in processes of manufacturing a display apparatus. In particular, the present invention relates to a defect repair apparatus and a defect repair method that are desirable for repairing a defect in a device pattern or a wiring pattern formed on a substrate such as a TFT (thin film transistor) substrate of a flat panel display (FPD).
2. Description of the Related Art
These days, as a display apparatus, a so-called flat panel display such as an organic EL (electro-luminescence) display and a liquid crystal display is popular. The display apparatuses are each formed of a wiring substrate including various conductive members such as elements including a thin film transistor (TFT) and a capacitor and a plurality of wirings (e.g., signal wiring and potential supply wiring) electrically connected to the elements.
In mass production of the wiring substrate that partly constitutes the display apparatus, a so-called defect such as a short circuit and disconnection may sometimes be generated by a foreign substance, for example. The short circuit means that a wiring and an element that are normally separate are electrically connected with each other. The disconnection means that a wiring and an element that are normally continuously provided are separated from each other. In the mass production, with increasing size of the display apparatus, the number of defects generated in a TFT substrate serving as a wiring substrate for driving the display apparatus is increased, which results in reduction in yield. To prevent this, defect repair processes for repairing defects are necessary.
As a technique of repairing the defect such as the short circuit and the disconnection, a technique of disconnecting a short-circuited portion through irradiation with laser light (laser repair), a technique of connecting a disconnected portion by a laser CVD (chemical vapor deposition) method, or the like is used.
For example, there has been proposed a defect repair method in which a defect repair technique is checked and selected based on CIM (computer integrated manufacturing) information on a substrate and defect coordinates, to thereby repair the defect automatically (see, for example, Japanese Patent Application Laid-open No. 2005-221974 (hereinafter, referred to as Patent Document 1)).
In addition, there has been proposed by the inventors of the present invention a defect repair method in which a unit pixel (wiring portion) on a substrate is sectioned into a plurality of areas and an appropriate repair technique is selected for each area, to thereby repair the defect (see, for example, Japanese Patent Application Laid-open No. 2008-159930 (hereinafter, referred to as Patent Document 2)).